Arlen Specter may not be a Republican anymore, but Karl Rove--who always tried to turn an opponent's strengths into weaknesses--would be proud of Specter's new line of attack against his likely Democratic primary opponent, Joe Sestak:

"Congressman Sestak is a flagrant hypocrite in challenging my being a real Democrat when he did not register as a Democrat until 2006 just in time to run for Congress," Specter said in the statement. "His lame excuse for avoiding party affiliation, because he was in the service, is undercut by his documented disinterest in the political process."

It will be interesting to see just how far Specter's willing to go in establishing his new Democratic bona fides. One avenue he appears to be taking (in addition to changing his policy positions): his byline. He's been writing, lately, for the New York Review of Books. How long before he starts blogging for Huffington Post?

--Jason Zengerle